JP2019170254A - Implement - Google Patents

Abstract

To provide an implement capable of performing highly accurately lift control of a work device by a land-leveling float, without complicating a driving system of a land-leveling rotor.SOLUTION: An implement includes a seedling planting device provided liftably through a link mechanism on the rear of a machine body, and lifting following a field based on displacement of a center float 9 in contact with the field, and a ground-leveling device arranged on the furthermore front side than the seedling planting device, lifting together with the seedling planting device, and having a ground-leveling rotor R driven rotatively around a driving shaft core in a lateral posture, in which, in the ground leveling rotor R, a small diameter part Ra is formed on a site adjacent to a convergent part of the center float 9.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a work machine in which a work device is provided at a rear end of the machine body so as to be movable up and down, and a leveling device having a leveling rotor is disposed on the front side of the work device.

  As a working machine having the above-described configuration, Patent Document 1 does not describe the point of raising / lowering the working device (planting unit in the literature) based on the displacement of the float, but the working device is freely raised and lowered at the rear end of the machine body. There is shown a technique of a working machine that is provided so that it can be moved up and down and has a leveling rotor (a scraping rotor in the literature) arranged on the front side of the working device.

  Further, Patent Document 2 includes a working device technology that includes a working device (in the literature, a seedling planting unit) that moves up and down following the field based on the displacement of the float, and that includes a leveling rotor on the front side of the working device. It is shown.

Japanese Patent Laid-Open No. 09-140215 JP 2007-300903 A

  As described in Patent Document 2, in a working machine in which the working device is controlled to move up and down based on the attitude of the float, in order to eliminate the inconvenience of frequently raising and lowering the working device in response to small irregularities on the surface of the field In addition, it is necessary to increase the ground contact area of the float.

  Also, when considering the timing of control, for example, when performing control to raise the work device corresponding to the rising part of the surface, if the control surface is taken into account and the rising surface of the surface is reached as the aircraft runs Therefore, it is required to detect the climax early and perform quick control. For this reason, there also exists a surface which wants to ensure the protrusion amount to the front of a float.

  In addition, in the configuration in which the leveling device having the leveling rotor is arranged on the front side of the work device, the leveling device is arranged in a limited space between the rear wheel of the machine body and the work device, so it is desirable to avoid increasing the size of the leveling device. There was a face.

  From this point of view, among the plurality of rotors provided along the left-right direction of the leveling rotor, as shown in Patent Document 2, in the configuration in which the rotor at the central portion is displaced forward and arranged, the float is small. The float can be arranged at a position suitable for sensing without making it easy. However, in the configuration in which the leveling rotor is arranged in this way, the drive structure of the leveling rotor is complicated, and the size of the leveling rotor is increased.

  On the other hand, as shown in Patent Document 1, when the leveling rotor can be driven by a single drive shaft in a lateral orientation, the drive system can be simplified and the increase in size can be suppressed. It becomes difficult to arrange in the position.

  For these reasons, there is a need for a work machine that can perform high-precision control of the working device using the leveling float without complicating the drive system of the leveling rotor.

  The working machine according to the present invention includes a working device that is provided at a rear portion of the machine body so as to be movable up and down via a link mechanism, and that moves up and down following the field surface based on a displacement of a float that contacts the field surface. A large-diameter portion that is disposed on the front side and includes a leveling device having a leveling rotor that moves up and down together with the working device and that rotates around a drive shaft core in a lateral orientation, and the leveling rotor performs leveling by driving rotation, and The small diameter portion which is smaller in diameter than the large diameter portion is formed in a portion facing the tapered portion of the float.

According to this feature configuration, since the leveling rotor is configured to drive and rotate about the drive shaft core in the lateral orientation, the drive system is simple and suppression of an increase in size is realized. Further, by making the portion adjacent to the tapered portion of the float of the leveling rotor a small diameter portion, for example, the tapered portion of the float is compared with a configuration in which the leveling rotor has an equal outer diameter over the entire length. Without inconvenience of touching, the float can be disposed at a position displaced forward, and the float need not be made compact.
In particular, it is difficult to level the surface at the small-diameter portion of the leveling rotor, but because the float is placed behind this small-diameter portion, the float touches the surface that could not be leveled by the leveling rotor, and the leveling is done. As a result, the area where no leveling is performed is not left on the surface.
Accordingly, a working machine has been constructed that can precisely control the lifting and lowering of the working device by the leveling float without complicating the drive system of the leveling rotor.

  As another configuration, the tapered distal end portion of the float and the large diameter portion may be arranged at a position where they overlap in a side view.

  According to this, it becomes possible to displace and arrange the float to the front side, and since the float can be used so as to have a large ground contact area, useless lifting control can be suppressed.

  As another configuration, the leveling rotor forms the large-diameter portion by externally fitting a leveling body to a drive shaft in a lateral orientation, and a protective cover having a smaller diameter than the leveling body is externally fitted to the drive shaft. The small-diameter portion is thus formed, and the fitting cover is formed on the inner periphery so that the protective cover is held in a fixed posture with respect to the drive shaft about the drive shaft core. good.

  According to this, a large diameter part can be formed by externally fitting a leveling body to a drive shaft, and a small diameter part can be formed by externally fitting a protective cover to the drive shaft. In addition, by holding the protective cover on the drive shaft by the fitting holding portion, it is possible to determine the posture of the protective cover around the drive shaft core. The protective cover originally does not have a leveling function, but for example, by making the cross section of the outer peripheral portion a polygonal shape, for example, a slight leveling can be expected by contacting the protruding portion of the rice field.

  As another configuration, the leveling rotor drives the lower link on the lower side, the upper link on the upper side, the lower link, and the upper link as a parallel quadruple link mechanism that supports the work device so as to be movable up and down. Each of the base ends is supported by a support frame of the working device so that the lower link and the upper link protrude forward, and the upper link is supported by the lower link. The positional relationship may be set so as to be located behind the link, and the elevating drive unit may be disposed above the upper link.

  According to this, the leveling rotor can be lifted / lowered by swinging the upper link and swinging the lower link by the lift drive unit. In this configuration, the lower link and the upper link are supported by the support frame of the work device so as to protrude forward, and further, the upper link is positioned behind the lower link, so that the upper link is located above the upper link. The lift drive unit to be arranged is brought close to the support frame, and the motors constituting the lift drive unit can be stably supported on the frame, and the lifting locus of the leveling rotor can be optimized.

  As another configuration, a cover body that covers the lower link and the upper link may be provided.

  According to this, a smooth operation is realized by suppressing the phenomenon that mud adheres to the lower link and the upper link.

It is a left view of a riding type rice transplanter. It is a schematic plan view of a seedling planting device and a leveling device. It is a vertical left view which shows the support structure and raising / lowering structure of a leveling apparatus. It is a left view which shows the transmission system from a rear axle case to a leveling apparatus. It is a cross-sectional plan view near the leveling input unit and the center float of the leveling device. It is sectional drawing of a drive shaft and a protective cover. It is a disassembled perspective view which shows the structure of the site | part of a support bracket. It is a cross-sectional plan view of a rear axle case. It is a vertical left side view of a rear axle case. It is a perspective view which shows the relationship between the rear boss | hub part of a rear axle case, and a control plate. It is a side view of the connection mechanism of a connection state. It is a side view of a connection mechanism in which a lock ring is in an unlocked position. It is a side view of the connection mechanism of a separation state. It is the schematic which shows the connection state of a control apparatus and each part.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a riding rice transplanter that is an example of a working machine in an embodiment of the present invention. The front-rear direction and the left-right direction in this embodiment are described as follows unless otherwise specified. The traveling direction of the forward side during traveling of the airframe 11 is “front”, and the traveling direction of the backward side is “rear”. The direction corresponding to the right side is “right” and the direction corresponding to the left side is “left” based on the forward posture in the front-rear direction.

(Overall structure of riding type rice transplanter)
As shown in FIG. 1, the riding type rice transplanter has a link mechanism 3 extending rearward at the rear part of a body 11 having a right and left front wheel 1 and a right and left rear wheel 2. A hydraulic cylinder 4 for moving the link mechanism 3 up and down is provided.

  A seedling planting device 5 (an example of a working device) is supported on the rear portion of the link mechanism 3, and a leveling device 26 is supported on the front side of the seedling planting device 5. The airframe 11 is provided with a steering handle 14 for steering the driver's seat 13 and the front wheel 1.

(Overall structure of seedling planting device)
As shown in FIGS. 1 and 2, the seedling planting device 5 includes a support frame 12, a feed case 15, a planting transmission case 6, a rotating case 7, a planting arm 8, a center float 9, side floats 53 and 54, seedlings. A stage 10 and the like are provided.

  As shown in FIG. 2, the center float 9 is supported (arranged) on the left and right center of the seedling planting device 5 in plan view. Side floats 53 and 54 are supported (arranged) on the right and left sides of the center float 9 in plan view.

  The support frame 12 is made of a pipe material having a rectangular cross section, and is arranged along the left-right direction at the front portion of the lower portion of the seedling planting device 5. A feed case 15 is connected to the left and right central portions of the support frame 12.

  As shown in FIGS. 1, 2, and 4, the link mechanism 3 is connected to the rear portion of the top link 3a and the lower link 3b, and the top link 3a and the lower link 3b supported by the body 11 so as to be swingable up and down. A link 3c is provided. As a result, the link mechanism 3 becomes a parallel quadruple type in a side view, and the feed case 15 is connected to the lower part of the vertical link 3c of the link mechanism 3 so as to be able to roll around the rolling axis P11 in the front-rear direction. The attaching device 5 is supported so as to be able to roll about the rolling axis P11.

  Four planting transmission cases 6 are connected to the rear surface portion of the support frame 12 in a form extending in the left-right direction at a predetermined interval and extending rearward. A rotating case 7 is rotatably supported on the right side and left side of the rear portion of the planting transmission case 6, and a pair of planting arms 8 are rotatably supported on both ends of the rotating case 7.

  The feed case 15 reciprocates the seedling stage 10 left and right by the driving force transmitted from the machine body 11 via the work transmission shaft 25, and rotates the rotary case 7 in conjunction with the reciprocating operation.

  With this operation, the rotation case 7 is driven to rotate counterclockwise in FIG. 1 along with the reciprocating movement of the seedling table 10 to the left and right. The operation of taking out the seedling from the lower part and planting (supplying) it on the rice field G (see FIG. 14) is realized.

(Structure of the driving transmission system to the front and rear wheels)
As shown in FIG. 1, a mission case 17 is supported on the front part of the airframe 11, and an engine 19 is supported on a front frame 18 connected to the front part of the mission case 17.

  A hydrostatic type continuously variable transmission 20 is connected to the left lateral side of the transmission case 17, and the power of the engine 19 is transmitted to the continuously variable transmission 20 via the transmission belt 21. The continuously variable transmission 20 is configured to be variable in a stepless manner at the neutral position, the forward side, and the reverse side. The continuously variable transmission 20 is configured to be capable of shifting operation by a shift lever 22 provided on the left side of the steering handle 14.

  The power of the continuously variable transmission 20 is transmitted to the right and left front wheels 1 via an auxiliary transmission (not shown) and a front wheel differential device (not shown) inside the mission case 17. Further, a rear axle case 23 that supports the right and left rear wheels 2 is supported by the rear portion of the airframe 11, and the driving force branched immediately before the front wheel differential device is applied to the rear axle case 23 via the travel transmission shaft 24. Communicated.

(Rear axle case structure)
As shown in FIG. 1, the right and left upper links 42 extend rearward in a state where the upper and lower links 42 are supported by the lower portion of the body 11 so as to be swingable up and down. The right and left lower links 43 extend to the rear side in a state where the lower links 43 are supported by the lower portion of the body 11 so as to be swingable up and down.

  A rear axle case 23 is connected to the rear portions of the upper link 42 and the lower link 43, and a lateral rod (not shown) is connected across the body 11 and the rear axle case 23. The right and left suspension springs 44 are connected across the body 11 and the rear axle case 23. With the above configuration, the rear axle case 23 is attached to the rear portion of the airframe 11 by a five-link type suspension mechanism.

  As shown in FIGS. 2, 4, and 8, the rear axle case 23 is provided with a front boss portion 23 a facing forward in the horizontal direction on the front surface portion of the rear axle case 23, and a traveling input shaft 45 is provided on the front boss portion 23 a. Supported positively. The travel transmission shaft 24 (see FIG. 1) is connected to the travel input shaft 45, and the power from the transmission case 17 is transmitted to the travel input shaft 45.

  As shown in FIGS. 8 and 9, a rear wheel transmission shaft 46 is supported inside the rear axle case 23 along the left-right direction. Inside the rear axle case 23, a first bevel gear 45a formed integrally with the travel input shaft 45 is disposed. A second bevel gear 46a is connected to the rear wheel transmission shaft 46, and the first bevel gear 45a and the second bevel gear 46a are engaged with each other.

  Side clutches 47 are provided on the right and left sides of the rear wheel transmission shaft 46. A relay shaft 48 and a rear axle 49 are provided on the right and left sides of the rear axle case 23, and the rear wheel 2 is supported on the rear axle 49. The first transmission gear 47a of the side clutch 47 and the second transmission gear 48a of the relay shaft 48 are engaged, and the third transmission gear 48b of the relay shaft 48 and the transmission gear 49a of the rear axle 49 are engaged. Yes.

  With the above configuration, the power transmitted from the traveling transmission shaft 24 to the traveling input shaft 45 is transmitted from the first bevel gear 45a of the traveling input shaft 45 to the rear wheel transmission shaft 46 via the second bevel gear 46a. This is transmitted to the right and left rear wheels 2 via the clutch 47, the relay shaft 48, and the rear axle 49.

(Side clutch operation system structure)
As shown in FIG. 8, the side clutch 47 is urged in a transmission state by a side clutch spring 47b provided therein. A pair of support boss portions 23c are formed in the rear axle case 23, and a clutch operating shaft 50 is rotatably supported by each support boss portion 23c, and a steering member (not shown) for steering the front wheel 1 is operated. And a clutch operating arm 50 a of the clutch operating shaft 50 are connected by a linkage operating member 65.

  When the front wheel 1 is steered within a range of right and left set angles with the straight drive position in between, the right and left side clutch 47 is transmitted by the urging force of the side clutch spring 47b of the side clutch 47. The power is transmitted equally to the right and left rear wheels 2.

  When the front wheel 1 is steered to the right (left) beyond the right (left) setting angle, the right (left) linkage operation member 65 is pulled toward the steering member side of the front wheel 1 Thus, the right (left) clutch operating shaft 50 is rotated.

  When the right (left) clutch operating shaft 50 is rotated, the end of the right (left) clutch operating shaft 50 pushes the clutch operating cylinder shaft 64 toward the right (left) side clutch 47 side. Then, the right (left) side clutch 47 is operated in a disconnected state against the urging force of the side clutch spring 47b of the right (left) side clutch 47. As a result, power is transmitted to the left (right) (turning outside) rear wheel 2, and the right (left) (turning inside) rear wheel 2 rotates freely, so that a right turn (left turn) is performed. .

  After the turn, when the front wheel 1 is steered within the range of the right and left set angles, the right (left) side clutch 47 is operated in the transmission state by the side clutch spring 47b of the side clutch 47, The state returns to the state where power is transmitted to the right and left rear wheels 2.

  As shown in FIG. 8, a collar 66 is externally fitted to the clutch operation shaft 50 in the support boss portion 23 c of the rear axle case 23. A return spring 67 is externally fitted to the support boss portion 23 c of the rear axle case 23, one end of the return spring 67 is connected to the clutch operation arm 50 a of the clutch operation shaft 50, and the other end of the return spring 67. The part is connected to the rear axle case 23. In this configuration, a stopper member (not shown) for preventing the other end portion of the return spring 67 from coming off is attached to a portion where the other end portion of the return spring 67 is connected to the rear axle case 23. .

  The clutch operating shaft 50 is biased to the return side (the transmission state side of the side clutch 47) by the return spring 67. Accordingly, as described above, when the front wheel 1 is steered within the range of the right and left set angles, the right (left) side clutch 47 is brought into the transmission state by the side clutch spring 47b of the side clutch 47. In addition to being operated, the clutch operating shaft 50 is rotated to the return side (the transmission state side of the side clutch 47) by the return spring 67.

  A regulating member 68 is attached to the rear axle case 23. When the clutch operating shaft 50 is rotated to the return side (the transmission state side of the side clutch 47) by the return spring 67, the clutch operating arm 50a of the clutch operating shaft 50 hits the restricting member 68, so that the clutch operating shaft 50 returns. It is stopped at a predetermined position on the side.

(Structure of transmission system to seedling planting device)
As shown in FIG. 1, a transmission between gears (not shown) and a planting clutch 38 (see FIG. 14) are provided inside the mission case 17.

  In the transmission case 17, the power branched from between the continuously variable transmission 20 and the auxiliary transmission (refer to the previous section (the structure of the traveling transmission system to the front wheels and the rear wheels)) is transmitted between the stock transmission and the planting clutch 38. To the work transmission shaft 25, and is transmitted from the work transmission shaft 25 to a transmission mechanism (not shown) inside the feed case 15.

  The power of the work transmission shaft 25 is transmitted from the transmission mechanism of the feed case 15 to the lateral feed shaft (not shown) of the seedling stage 10, and the planting transmission case is transmitted via the transmission shaft (not shown). 6 and transmitted to the rotating case 7 via a transmission mechanism (not shown) inside the planting transmission case 6.

(Raising / lowering structure of seedling planting device by lifting / lowering operation lever)
As shown in FIGS. 1 and 14, an elevating operation lever 39 is provided on the right side of the driver seat 13. The raising / lowering operation lever 39 can be operated to an ascending position, a neutral position, a descending position, and a planting position, and is mechanically connected to the planting clutch 38.

  As shown in FIG. 14, the airframe 11 is provided with a control device 40, and the operation position of the elevating operation lever 39 is input to the control device 40. The hydraulic cylinder 4 is provided with a control valve 41 of an electromagnetic operation type for supplying and discharging hydraulic oil, and the control valve 41 is operated by the control device 40. In addition, when the elevating operation lever 39 is operated to the raised position, neutral position, lowered position, and planting position, the control valve 41 and the planting clutch 38 are operated as follows.

  When the raising / lowering operation lever 39 is operated to the raised position, the planting clutch 38 is operated to the disconnected state, the control valve 41 is operated to the raised position, the hydraulic cylinder 4 is contracted, and the seedling planting device 5 is operated. To rise.

  When the raising / lowering operation lever 39 is operated to the neutral position, the planting clutch 38 is operated to the disconnected state, the control valve 41 is operated to the neutral position, the hydraulic cylinder 4 is stopped, and the seedling planting device 5 is moved up and down. Stops.

  When the raising / lowering operation lever 39 is operated to the lowered position, the planting clutch 38 is operated to the disconnected state, the control valve 41 is operated to the lowered position, the hydraulic cylinder 4 is extended, and the seedling planting device 5 is operated. Descend.

  When the center float 9 touches the surface G in the state in which the elevating operation lever 39 is operated to the lowered position, the elevating control of the seedling planting device 5 is actuated as described later (Elevating control of the seedling planting device). It becomes a state to do. Thereby, the control valve 41 and the hydraulic cylinder 4 are operated so that the seedling planting device 5 is automatically moved up and down so that the planting depth of the seedling by the planting arm 8 is maintained at the set depth. .

  When the raising / lowering operation lever 39 is operated to the planting position, the raising / lowering control of the seedling planting device 5 is activated and the planting clutch 38 is operated to the transmission state as in the above-described lowering position. Further, when the planting clutch 38 is operated in the transmission state, power is transmitted to the seedling planting device 5, and the seedling planting device 5 is operated as described in the above-mentioned (Entire configuration of the seedling planting device). Operate.

  In particular, in this riding type rice transplanter, when transporting using a truck or the like, the rice transplanter is mounted on a loading platform such as a truck, and the seedling planting device 5 is raised during such transport. Two stands are used so as to support the seedling planting device 5 so as to maintain the raised state and to maintain the raised state. The two stands are used in a form of being arranged below the side floats 53, 54 and the like.

  By using the two stands in this way, the load of the seedling planting device 5 can be received, and the shaking of the seedling planting device 5 can be satisfactorily suppressed, and the side floats 53 and 54 are brought into contact with the bed etc. and are damaged. Inconvenience can be solved. For this reason, enlargement of the side floats 53 and 54 is permitted.

(Elevation control of seedling planting device)
In this riding type rice transplanter, as shown in FIG. 14, the link mechanism 3 is moved up and down by the hydraulic cylinder 4 so that the seedling planting device 5 is maintained at the set level H <b> 1 from the rice field G, and the seedling planting device 5. Is controlled by the control device 40 that maintains the planting depth of the seedling by the planting arm 8 at the set depth.

  A support shaft 55 is supported at the lower part of the planting transmission case 6 so as to be rotatable around a pivot shaft P5 in the left-right direction, and a support arm 55a connected to the support shaft 55 extends rearward. Yes. The rear portions of the center float 9 and the side floats 53 and 54 are supported so as to be swingable up and down around a support shaft core P6 in the left-right direction at the rear portion of the support arm 55a.

  A support bracket 120 shown in FIG. 7 is provided on the upper surfaces of the center float 9 and the side floats 53 and 54. As shown in FIGS. 7 and 14, a rectangular hole 121 a is formed in each of the pair of support plate portions 121 in the vertical orientation formed in the support bracket 120.

  As a specific configuration, a resin bush 122 is fitted into each of the support plate portions 121 in a rectangular hole portion 121a, and a float support shaft 123 inserted into the through hole of the bush 122 is connected to a support hole portion 55b at the rear end of the support arm 55a. Is inserted. Further, a restricting plate 124 is fixed by welding to one outer end of the float support shaft 123, and the front end of the restricting plate 124 is engaged with a restricting pin 55c protruding outward from the support arm 55a.

  The bush 122 is formed with a through hole and has a rectangular bush body 122a, and has a disc-shaped flange portion 122b at one end. When attaching to the support plate portion 121, the rectangular bushing body 122 a is inserted into the rectangular hole portion 121 a from the inside (the center side in the width direction) of the support plate portion 121, and the flange portion 122 b is brought into contact with the inner surface of the support plate portion 121. It is arranged in a state to let it.

  The restriction plate 124 is formed with a circular support hole 124a through which the float support shaft 123 is inserted, and an oblong engagement hole 124b that is long in the front-rear direction so that the restriction pin 55c is inserted therethrough.

  By providing the restriction plate 124 in this manner, the swing of the center float 9 and the side floats 53 and 54 around the axis of the float support shaft 123 is restricted. By restricting the swinging in this way, it is possible to suppress the inconvenience that the center float 9 and the front end portions of the side floats 53 and 54 droop greatly when the seedling planting device 5 is raised.

  In particular, since the resin bush 122 is externally fitted to the float support shaft 123, direct contact between the float support shaft 123 and the support bracket 120 is suppressed, and these wears are suppressed. If the bush 122 is worn, it can be dealt with by replacing the bush 122.

  The planting depth lever 56 is connected to the support shaft 55 and extends obliquely forward, and the planting depth lever 56 is inserted into the lever guide 57 connected to the support frame 12. By engaging and fixing the planting depth lever 56 to the lever guide 57, the position of the support shaft core P6 (support arm 55a of the support shaft 55) is determined with respect to the seedling planting device 5, and the setting level H1 Is decided.

  A potentiometer type level sensor 58 is supported by the support frame 12, and extends across the detection arm 58 a of the level sensor 58 and the front part of the center float 9. A linkage member 59 is connected.

  With the above configuration, the height from the surface G (center float 9) to the seedling planting device 5 is detected by the level sensor 58 via the linking member 59 with respect to the center float 9 following the ground contact with the surface G. The detection value of the level sensor 58 is input to the control device 40.

  Based on the detection value of the level sensor 58, the control valve 41 is operated by the control device 40, the hydraulic cylinder 4 is expanded and contracted, and the seedling planting device 5 is maintained from the rice field G to the set level H1. The planting device 5 is moved up and down. Thereby, the planting depth of the seedling by the planting arm 8 is maintained at the set depth corresponding to the set level H1.

  By operating the planting depth lever 56 and changing the position of the support shaft core P6 (support arm 55a of the support shaft 55), the setting level H1 can be changed. Thereby, the seedling planting device 5 is moved up and down so as to be maintained at the changed setting level H1, and the planting depth (set depth) of the seedling by the planting arm 8 can be changed. it can.

(Overall structure of leveling device)
As shown in FIGS. 2 and 3, the leveling device 26 includes a leveling rotor R. That is, the leveling rotor R is leveled to level the field G by being attached to the drive shaft 34 coaxially disposed with the drive shaft core X in the lateral orientation, and being driven to rotate integrally with the drive shaft 34. The body 35, the leveling input unit 29 and the shaft support unit 30 that rotatably support the drive shaft 34, a mud removing cover 36, a protective cover 37, and the like are provided.

  The drive shaft 34 is made of a pipe material having a square cross-sectional shape. As shown in FIGS. 5 and 6, a resin leveling body 35 is fitted on the drive shaft 34, and the resin leveling body 35 is made of resin. The leveling rotor R is configured by externally fitting a protective cover 37 having a smaller diameter, and the protective cover 37 forms a small-diameter portion Ra of the leveling rotor R. In the leveling rotor R, the portion including the leveling body 35 is a large diameter portion.

  As shown in FIG. 6, the protective cover 37 has a plurality of protrusions 37 </ b> S along the longitudinal direction formed on the outer surface, and a fitting holding portion 37 </ b> T that fits the drive shaft 34. When the fitting holding portion 37T is fitted to the drive shaft 34, the position of the protective cover 37 is determined, and the protective cover 37 rotates integrally with the drive shaft 34.

  As described above, the center float 9 is disposed at the center of the seedling planting device 5 in the left-right direction, and the raising / lowering control of the seedling planting device 5 is performed from the swinging posture of the center float 9. The center float 9 is disposed at a position where the tip 9 a (tapered portion) faces the protective cover 37. Specifically, the front end 9a (tapered portion) of the center float 9 is disposed in front of the rear end position of the leveling body 35 and slightly behind the protective cover 37 constituting the small diameter portion Ra in a plan view shown in FIG. ing.

  Thereby, the front end position of the center float 9 can be displaced in the vertical direction without the tip 9a contacting the leveling body 35. The center float 9 can be enlarged in the front-rear direction to suppress erroneous detection, and the entire center float 9 is displaced forward so that the state of the surface G can be detected at an early timing. Yes.

  Furthermore, since the entire width of the center float 9 is set to be larger than the entire length of the protective cover 37, an area that cannot be leveled by the leveling body 35 on the surface G can be leveled by the center float 9.

  In the seedling planting device 5, the leveling device 26 is supported by the support frame 12 as described below, as described later (supporting structure of the leveling device). That is, the leveling device 26 is disposed between the seedling planting device 5 and the rear axle case 23 (rear wheel 2) in a side view as shown in FIG.

(Support structure for leveling device)
As shown in FIGS. 2, 3, and 4, a pair of left and right brackets 27 are connected to the front surface portion of the support frame 12 and extend to the front side. A round pipe-shaped operating shaft 28 is supported by the front end portions of the left and right brackets 27 in a posture along the support frame 12 so as to be rotatable around the first axial core P1 in the left-right direction.

  Three lower link arms 28a (an example of a lower link) are connected to the operating shaft 28 in a posture protruding forward. The leveling input portion 29 and the arm bodies 29a, 30a of the shaft support portion 30 are supported at the front end portion of the lower link arm 28a of the operating shaft 28 so as to be swingable around the second axis P2 in the left-right direction.

  An upper link arm 98 (an example of an upper link) is supported swingably up and down around the third axis P3 in the left-right direction with respect to the upper portion of the bracket 27, and a leveling input is input to the front end of the upper link arm 98. The arm bodies 29a and 30a of the portion 29 and the shaft support portion 30 are supported so as to be swingable about the fourth axis P4 in the left-right direction. With the above structure, the support mechanism 51 is configured to include the bracket 27, the operation shaft 28, the lower link arm 28 a, and the upper link arm 98. Accordingly, the lower link arm 28a and the upper link arm 98 constitute a parallel quadruple link mechanism in a side view.

  As described above, the leveling input unit 29 and the shaft support unit 30 of the leveling device 26 are supported by the support frame 12 via the support mechanism 51. Then, as will be described later (elevating structure of the leveling device), the leveling device 26 is operated by rotating (swinging) the operating shaft 28 (lower link arm 28a) about the first axis P1. Can be moved up and down with respect to the seedling planting device 5 (support frame 12).

(Elevating structure of leveling device)
As shown in FIGS. 2, 3, and 5, in the support frame 12, the support member 16 is connected and extended upward near the lower link arm 28 a at the center of the operating shaft 28. In the support plate 16a supported by the support member 16, a fan-shaped elevating gear 31 is swingably supported around the third axis P3 in a side view.

  The front end of the elevating gear 31 is connected to the upper part of the arm body 29a of the leveling input unit 29 so as to be swingable about the fourth axis P4. A gear case 32 and an electric motor 33 are supported by the support member 16, and a pinion gear 32 a of the gear case 32 is engaged with the elevating gear 31. An assist spring 63 is connected across the upper portion of the support member 16 and the leveling input unit 29, and the leveling device 26 is urged upward by the assist spring 63.

  With the above-described structure, the elevating drive unit 52 includes the elevating gear 31, the gear case 32 (pinion gear 32a), and the electric motor 33. Further, as shown in FIG. 2, a cover body 130 is provided at the front positions of the lower link arm 28 a and the upper link arm 98 to protect them. By providing the cover body 130 in this manner, it is possible to eliminate the disadvantage that mud adheres to the lower link arm 28a and the upper link arm 98.

  In the elevating drive unit 52, the pinion gear 32a of the gear case 32 is rotationally driven by the electric motor 33, whereby the elevating gear 31 is driven to swing up and down around the third axis P3 and is operated via the leveling input unit 29. The lower link arm 28a of the shaft 28 is swung up and down to change the position of the leveling device 26 up and down.

  In particular, as shown in FIGS. 3 and 4, the lower link arm 28a (an example of the lower link) and the upper link arm 98 (an example of the upper link) are attached to the support frame 12 via the bracket 27 so as to protrude forward. It is supported. Further, in this configuration, the positional relationship is set so that the upper link arm 98 is located behind the lower link arm 28a. Further, in the elevating gear 31 constituting the elevating drive unit 52, a portion overlapping with the upper link arm 98 in a side view functions as a link arm like the upper link arm 98.

  In this configuration, since the upper link arm 98 is disposed rearward compared to the position of the lower link arm 28a, the lifting gear 31 partially overlapping with the upper link arm 98 in a side view can be disposed rearward. The elevating drive unit 52 can be brought close to the support frame 12, and the elevating drive unit 52 can be stably supported on the support frame 12 via the support member 16. To achieve proper elevation.

(Structure on the rear axle case side in the transmission system to the leveling device)
As shown in FIGS. 4, 8, and 9, the rear axle case 23 is provided with a rear boss portion 23 b that is obliquely downward and rearward on the rear surface portion of the rear axle case 23. An output shaft 60 is supported on the rear boss portion 23b, and the output shaft 60 is supported obliquely downward and rearward on the rear surface portion of the rear axle case 23.

  In the rear axle case 23 (rear boss portion 23 b), a third bevel gear 61 is externally fitted to the output shaft 60 so as to be relatively rotatable, and the third bevel gear 61 is connected to the second bevel gear 46 a of the rear wheel transmission shaft 46. Biting.

  A leveling clutch 62 is provided between the output shaft 60 and the third bevel gear 61 inside the rear axle case 23 (rear boss portion 23 b). The leveling clutch 62 includes a shift member 69 that rotates together with the output shaft 60 and is slidably fitted to the output shaft 60 by spline fitting to the output shaft 60 inside the rear boss portion 23b. Is provided in the direction of the third bevel gear 61. The leveling clutch 62 has a structure that reaches the transmission state when the tooth portion at the end of the shift member 69 is engaged with the tooth portion at the rear end of the third bevel gear 61.

In the leveling clutch 62, the shift member 69 is operated to the transmission position engaged with the third bevel gear 61 by the urging force of the clutch spring 70, whereby the power of the travel input shaft 45 is transmitted from the second bevel gear 46a of the rear wheel transmission shaft 46. It is transmitted to the output shaft 60 via the third bevel gear 61. As will be described later (structure on the leveling device side in the transmission system to the leveling device), it is transmitted from the output shaft 60 to the leveling device 26 (leveling input unit 29) via the leveling transmission shaft 71.
In the leveling clutch 62, the transmission of power from the traveling input shaft 45 to the output shaft 60 is cut off by operating the shift member 69 to the cut-off position away from the third bevel gear 61 against the clutch spring 70.

  The inner diameter of the front boss portion 23 a of the rear axle case 23 is set to be slightly larger than the outer diameter of the first bevel gear 45 a of the traveling input shaft 45. Thereby, the traveling input shaft 45 (first bevel gear 45a) can be extracted without difficulty from the front boss portion 23a of the rear axle case 23 in maintenance work or the like.

  The inner diameter of the rear boss portion 23 b of the rear axle case 23 is set to be slightly larger than the outer diameter of the third bevel gear 61 of the output shaft 60. Thereby, the output shaft 60 (the third bevel gear 61) and the leveling clutch 62 can be extracted without difficulty from the rear boss portion 23b of the rear axle case 23 in maintenance work or the like.

(Structure of the leveling clutch operating system)
As shown in FIGS. 4 and 8, in the leveling clutch 62, the clutch control shaft 72 that operates the shift member 69 to the shut-off position against the clutch spring 70 is rotatable to the rear boss portion 23 b of the rear axle case 23. It is supported. A leveling clutch operating mechanism 76 is provided across the lower link 3 b of the link mechanism 3 and the clutch control shaft 72. The clutch control shaft 72 has a fork portion at the inner end for operating the shift member 69 to the cutoff position.

  As shown in FIG. 4, a spring support member 73 is attached to the lower link 3b of the link mechanism 3, the operation rod 74 is inserted into the spring support member 73 so as to be slidable up and down, and the lower end portion of the operation rod 74 is connected to the clutch control shaft. 72 is connected to the clutch control arm 72a. A buffer spring 75 is fitted on the upper portion of the operating rod 74 above the spring support member 73.

  In this configuration, as shown in FIG. 8 and FIG. 10, by forming a tapered surface at the outer end of the clutch control shaft 72, the outer end is formed into a tapered shape, and the regulating plate that prevents the clutch control shaft 72 from being removed. 101 is fixed to the rear boss portion 23b by a plurality of fixing bolts 102. With the restriction plate 101 fixed, a slight gap is formed between the outer end of the clutch control shaft 72 and the restriction plate 101.

  As described above, the leveling clutch operation mechanism 76 includes the spring support member 73, the operation rod 74, the buffer spring 75, and the restriction plate 101. When the link mechanism 3 (seedling planting device) is lifted and lowered as described above (lifting structure of the seedling planting device by the lifting operation lever), the leveling clutch 62 is moved by the leveling clutch operating mechanism 76 as follows. It is operated to the transmission position and the cutoff position as described.

  When the link mechanism 3 is lowered to a position where the seedling planting device 5 (the center float 9 and the side floats 53 and 54) contacts the surface G, the operation rod 74 is in the lowered state, so that the clutch control of the clutch control shaft 72 is performed. The arm 72a is not operated, and the shift member 69 (leveling clutch 62) is operated to the transmission position by the clutch spring 70.

  When the link mechanism 3 is raised, the spring support member 73 is raised as the lower link 3b is raised. At this time, the upper end of the buffer spring 75 comes into contact with the spring receiving portion 74 a at the upper end of the operation rod 74, and then the buffer spring 75 is compressed and a force acts on the operation rod 74 in the lifting direction. When the force acts in the lifting direction as described above, the leveling clutch 62 is operated to the disengaged position by operating the clutch control arm 72a with the force from the operating rod 74 while the buffer spring 75 is compressed.

  The timing at which the leveling clutch 62 is shut off is set to the time when the center float 9 and the like of the seedling planting device 5 reach a height away from the paddy field G. In addition, when the leveling clutch 62 reaches the disengaged state and the shift member 69 reaches the operating limit, the buffer spring 75 is compressed, so that excessive external force is not applied to the shift member 69 and the leveling clutch 62 is operated. The inconvenience that breaks is suppressed.

  Further, since a tapered surface is formed at the outer end of the clutch control shaft 72, finishing of the outer end portion of the clutch control shaft 72 can be easily performed, and this outer end portion may come into contact with the regulation plate 101. Also, the resistance acting on the rotation of the clutch control shaft 72 can be reduced. Furthermore, by forming a gap between the outer end of the clutch control shaft 72 and the inner surface of the regulating plate 101, assembly becomes easy, and clearance management is also facilitated.

  As a result, the clutch control shaft 72 is rotated, and the shift member 69 (leveling clutch 62) is operated to the cutoff position against the clutch spring 70. Further, when the link mechanism 3 is further raised after the shift member 69 (the leveling clutch 62) reaches the cutoff position, the buffer spring 75 is compressed, so that the shift member 69 (the leveling clutch 62) is moved to the cutoff position. It is not manipulated to exceed.

(Structure on the leveling device side in the transmission system to the leveling device)
As shown in FIGS. 2, 4, and 5, in the leveling device 26, the drive shaft 34 is supported by the leveling input unit 29 and the shaft support unit 30 so as to be rotatable about the drive shaft core X in the lateral orientation. In addition, a protective cover 37 whose outer surface is circular in cross section at the center portion of the drive shaft 34 is fitted on the drive shaft 34 so as to rotate integrally with the drive shaft 34. The protective cover 37 is disposed on the front side of the center float 9 and has a lateral width that is substantially the same as the lateral width of the front portion of the center float 9.

  The leveling input unit 29 is disposed at the left end of the protective cover 37, and the leveling input unit 29 is disposed at the left side of the front portion of the center float 9 in the drive shaft 34. Thereby, the front part of the center float 9 is in a state of entering between the right leveling body 35 and the leveling input part 29 (left leveling body 35) in a plan view. The front part of the center float 9 overlaps with the leveling input unit 29 (leveling body 35) in a side view.

  As shown in FIGS. 4 and 5, the leveling input unit 29 is provided with an input boss portion 29 b that is obliquely upward and forwards on the front surface of the leveling input unit 29. An input shaft 77 is supported on the input boss portion 29b diagonally upward.

  As shown in FIGS. 2 and 4, the front portion of the leveling shaft 71 is connected to the output shaft 60 (see FIGS. 8 and 9) of the rear axle case 23 via the first universal joint 78. The rear portion of the leveling shaft 71 is connected to the input shaft 77 (see FIG. 5) of the leveling input portion 29 via the second universal joint 79.

  As shown in FIG. 5, an input bevel gear 77 a is integrally provided on the input shaft 77 inside the leveling input unit 29. A drive bevel gear 37a is connected to the left side (opposite the center float 9) of the protective cover 37 with respect to the input bevel gear 77a of the input shaft 77. The input bevel gear 77a of the input shaft 77 and the drive bevel gear 37a of the protective cover 37 are engaged with each other.

(Leveling condition of leveling device)
As described above (the structure on the rear axle case side in the transmission system to the leveling device) and as shown in FIG. 8, when the leveling clutch 62 is operated to the transmission position, the rear axle case 23 receives the traveling input. The power of the shaft 45 is transmitted from the second bevel gear 46a of the rear wheel transmission shaft 46 to the output shaft 60 via the third bevel gear 61, and as shown in FIGS. Is transmitted to the input shaft 77 of the leveling device 26 (leveling input unit 29).

  As a result, in the leveling device 26, the drive shaft 34 is rotationally driven in the counterclockwise direction of FIGS. The ground surface 35 is leveled by the leveling body 35 of the leveling rotor R by rotating the leveling body 35 integrally with the drive shaft 34, and even if mud is blown to the rear side by the leveling body 35, it is blown away. The mud is prevented from being scattered by the mud removal cover 36.

  As shown in FIG. 2, the shaft support portion 30 is positioned on the rear side of the rear wheel 2, and the leveling device 35 is not provided in the portion of the shaft support portion 30 in the leveling device 26. The side float 53 is located on the side. The passage of the rear wheel 2 is not leveled by the leveling device 26, and the unevenness of the surface G is leveled by the side float 53.

  Similarly to the above, the leveling body 35 is not provided in the protective cover 37 portion of the leveling device 26, but the center float 9 is located behind the protective cover 37. In the portion of the protective cover 37, the leveling by the leveling device 26 is not performed, and the unevenness of the surface G is leveled by the center float 9.

  As described in the section (Structure on the rear axle case side in the transmission system to the leveling device), when the leveling clutch 62 is operated to the disengagement position, in the rear axle case 23, the traveling input shaft 45 is changed to the output shaft 60. Is interrupted and the leveling device 26 (drive shaft 34) stops.

(Structure of leveling shaft)
As shown in FIG. 4, the leveling transmission shaft 71 is provided with a spline shaft 80, a spline cylinder shaft 81, and a cover 82.

  The spline shaft 80 has a spline portion formed on the outer surface, and is connected to the output shaft 60 of the rear axle case 23 via the first universal joint 78. The spline cylinder shaft 81 has a cylindrical shape with a spline portion formed on the inner surface, and is connected to the input shaft 77 of the leveling device 26 (leveling input portion 29) via a second universal joint 79.

  The spline shaft 80 is inserted into the spline cylinder shaft 81, and the spline shaft 80 and the spline cylinder shaft 81 are slidably fitted to each other. The cover 82 is made of rubber and has a bellows shape, and is extendable and contractable. A cover 82 is attached across the spline shaft 80 and the end of the spline cylinder shaft 81, and the cover 82 covers a portion where the spline shaft 80 is inserted into the spline cylinder shaft 81.

  As shown in FIGS. 2 and 5, the front boss portion 23a and the rear boss portion 23b of the rear axle case 23 are on the right side in a plan view with respect to the left and right center line CL of the body 11 (the seedling planting device 5). It is arranged at a position that deviates.

  In addition, the input shaft 77 of the leveling device 26 (leveling input unit 29) is disposed at a position that deviates to the left in plan view with respect to the left-right center line CL. Thereby, the leveling transmission shaft 71 connected across the output shaft 60 and the input shaft 77 is disposed so as to obliquely intersect the left-right center line CL in plan view.

  The work transmission shaft 25 to the seedling planting device 5 is disposed at the position of the left and right center line CL so as to overlap the left and right center line CL in plan view, and is disposed above the rear axle case 23 and the leveling transmission shaft 71. Has been.

(Separation structure of leveling shaft)
As shown in FIG. 4, the leveling transmission shaft 71 is configured to be detachably connected from the output shaft 60 by the connection mechanism C at the site of the first universal joint 78 on the front end side. The connecting mechanism C can be configured to be separated by a simple human operation by providing the leveling transmission shaft 71 at the site of the second universal joint 79. In this embodiment, the first universal joint shaft C can be separated. The structure which enables isolation | separation in the site | part of the coupling 78 is shown.

  As shown in FIGS. 11 to 13, the portion of the output shaft 60 that protrudes to the outside from the rear boss portion 23 b has a hexagonal cross-sectional shape, and an annular groove-like engagement recess 60 a is formed on the outer periphery. . The first universal joint 78 includes a first yoke part 78a that is fitted on the output shaft 60, a second yoke part 78b that has a base end connected to the spline shaft 80, and a cross shaft 78c that is connected to these parts. .

  The coupling mechanism C includes a transmission cylinder shaft 105 that is fitted on the output shaft 60 of the first yoke portion 78a, a plurality of through holes 105a that penetrates along the radial direction in the transmission cylinder shaft 105, and a plurality of through holes 105a. Engagement balls 106 as engagement members fitted in each of these, and a lock ring 107 that is externally fitted to the transmission cylinder shaft 105 so as to be movable in a direction along the axis of the transmission cylinder shaft 105. . In the configuration of the coupling mechanism C, the engagement ball 106 is fitted into the engagement recess 60 a of the output shaft 60, thereby functioning to restrict separation of the first universal joint 78 from the output shaft 60.

  A stopper 108 is provided on the outer periphery of the transmission cylinder shaft 105, and a lock spring 109 as a biasing member for applying a biasing force to abut the lock ring 107 against the stopper 108, an end surface of the lock ring 107, and the first yoke portion. 78a.

  A smooth portion having a posture along the outer surface of the output shaft 60 is formed on the inner periphery of the lock ring 107, and a concave portion 107 a that is a space expanding outward from the outer surface of the output shaft 60 is formed.

  The lock ring 107 is configured to be freely operated at a lock position L that abuts against the stopper 108 and an unlock position F shown in FIG. 12 by an artificial operation against the urging force of the lock spring 109. When the lock ring 107 is in the lock position L, the smooth surface on the inner periphery of the lock ring 107 prevents the engagement ball 106 from lifting from the engagement recess 60a. On the contrary, when the lock ring 107 is operated to the unlock position F, the concave portion 107a of the lock ring 107 allows the engagement ball 106 to lift from the engagement concave portion 60a.

  From such a configuration, when the lock ring 107 is in the lock position L, the state in which the first universal joint 78 is connected to the output shaft 60 is maintained. When the lock ring 107 is manually operated to the unlock position F, the engagement of the engagement ball 106 with the engagement recess 60a is released, and the first universal joint 78 can be separated.

  In such a separated state, only the output shaft 60 protrudes rearward from the rear axle case 23. For example, compared with a configuration in which a part of the leveling transmission shaft 71 remains connected to the output shaft 60. Then, there is no inconvenience that a part of the leveling shaft 71 rotates when the output shaft 60 rotates in the detached state.

  Note that this separation operation is an operation for facilitating removal of the straw when the straw is wound around the leveling transmission shaft 71 during the work, and is also required during the maintenance. Further, since the output shaft 60 has a hexagonal cross-sectional shape, for example, it can be manufactured at a lower cost than a spline fitting structure, and the transmission cylinder shaft 105 is not fixed, and the surface area is smaller than the spline structure. Since it is difficult for water droplets to adhere, the occurrence of rust is also suppressed.

(Control system configuration)
As shown in FIG. 14, the seedling planting device 5 includes a depth setting unit 90 and a leveling setting operation unit 91, and operation signals from the depth setting unit 90 and the leveling setting operation unit 91 are transmitted to the control device 40. Has been entered. The leveling setting operation unit 91 is a push button type that is artificially pushed, and the depth setting unit 90 is a dial switch type that is artificially rotated.

  An operation position sensor 92 for detecting a support position of the center float 9 with respect to the seedling planting device 5 by detecting the operation position of the planting depth lever 56 is provided, and the detected value of the operation position sensor 92 is determined by the control device 40. Is input.

  A leveling position sensor 93 for detecting the support position of the leveling device 26 with respect to the seedling planting device 5 by detecting the angle of the elevating gear 31 is provided, and the detection value of the leveling position sensor 93 is input to the control device 40. The

  A potentiometer type link sensor 112 operated via an operating member 111 so as to detect the swinging amount of the link mechanism 3 is provided, and a detection signal of the link sensor 112 is input to the control device 40.

(Elevation control)
As shown in FIG. 14, based on the operation signals of the depth setting unit 90 and the leveling setting operation unit 91 and the detection values of the operation position sensor 92 and the leveling position sensor 93, the control device 40 performs electric driving as described below. The motor 33 is operated and the leveling device 26 is moved up and down.

  A work position where the leveling device 26 contacts the field surface G and a retreat position where the leveling device 26 is greatly raised from the field surface G are set. That is, the leveling device 26 at the retracted position can be lowered to the work position by pressing the leveling setting operation unit 91. Further, the leveling device 26 at the work position can be raised to the retracted position by pressing the leveling setting operation unit 91 again.

  In such lift control, when the link mechanism 3 exceeds the set value from the detection signal from the link sensor 112, the control device 40 controls the electric motor 33 so as to drive the leveling device 26 downward. Do. In this control, when the seedling planting device 5 exceeds a preset height, control is performed to lower the leveling device 26 by an amount corresponding to the amount exceeding the set value. The first universal joint 78 and the second universal joint 79 are not largely bent, and the action of an excessive external force is suppressed to protect the joint.

  In the state where the leveling device 26 is located at the work position, the leveling body 35 of the leveling device 26 slightly enters the surface G and rotates, so that the leveling of the field G is performed. Since the setting level H1 is detected by the operation position sensor 92 and the support position of the leveling device 26 with respect to the seedling planting device 5 is detected by the leveling position sensor 93, the height of the leveling device 26 with respect to the surface G is detected. Yes, the leveling depth at which the leveling body 35 of the leveling device 26 enters the field G is detected.

  By operating the depth setting unit 90, the set leveling depth can be set and changed. As described above, the leveling device 26 is moved up and down so that the leveling depth of the leveling device 26 becomes the set leveling depth by detecting the leveling depth of the leveling device 26.

  Since the leveling device 26 is supported by the seedling planting device 5 (support frame 12), the setting level H1 is changed by the planting depth lever 56 as described in the previous section (Control for raising and lowering the seedling planting device). Then (when the planting depth by the planting arm 8 is changed), the leveling depth of the leveling device 26 changes.

  When the setting level H1 is lowered by the planting depth lever 56 (when the planting depth by the planting arm 8 is increased), the leveling device 26 raises the seedling planting device 5 by an amount corresponding to the lower setting level H1. Is done. Thereby, the leveling depth of the leveling device 26 is maintained at the set leveling depth.

  When the setting level H1 is increased by the planting depth lever 56 (when the planting depth by the planting arm 8 is decreased), the leveling device 26 performs the lowering operation with respect to the seedling planting device 5 as much as the set level H1 is increased. Is done. Thereby, the leveling depth of the leveling device 26 is maintained at the set leveling depth.

[Another embodiment]
In addition to the above-described embodiments, the present invention may be configured as follows (the components having the same functions as those of the embodiments are given the same numbers and symbols as those of the embodiments).

(A) A position where the tip 9a of the float (center float 9 of the embodiment) overlaps with the protective cover 37 (small diameter portion) in a plan view or a position protruding forward from the protective cover 37 (small diameter portion) To place. By setting the positional relationship in this way, the front and rear length of the center float 9 can be increased.

  In the embodiment, the height of the rice field G is detected using the center float 9 at the center position in the left-right direction of the seedling planting device 5, but the float for detecting the height of the rice field G is In the case of the configuration deviating from the center position in the direction, the small-diameter portion Ra is formed in the leveling rotor R at a position corresponding to the float.

(B) The tip 9a of the float (center float 9 of the embodiment) is formed to be further tapered than that shown in the embodiment. In this way, by setting the shape of the tip of the float so as to be further tapered, it is possible to reduce the region where the small-diameter portion Ra is formed.

(C) The configuration of the present invention is applied to a direct seeder in addition to a rice transplanter. In the configuration of this another embodiment, a seeding device is provided as a working device at the rear end of the machine body 11, the leveling device 26 is disposed in front of the float of the seeding device, and the position of the leveling device 26 is opposed to the tip of the float The small-diameter portion Ra of the leveling rotor R is formed.

  INDUSTRIAL APPLICABILITY The present invention can be used for a working machine that includes a working device that can be raised and lowered at the rear end of the machine body, and that has a leveling device having a leveling rotor on the front side of the working device.

3 Link mechanism 5 Seedling planting device (working device)
9 Center float (float)
11 Airframe 12 Support frame 26 Leveling device 28a Lower link arm (lower link)
34 Drive shaft 35 Leveling body 37 Protective cover 37T Fitting holding part 52 Lifting drive part 98 Upper link arm (upper link)
130 cover body G surface R leveling rotor Ra small diameter part X drive shaft core

Claims (5)

A working device that is provided at the rear of the machine body so as to be movable up and down via a link mechanism, and that moves up and down following the field surface based on the displacement of the float that contacts the field surface,
A ground leveling device that is disposed on the front side of the work device, moves up and down with the work device, and has a leveling rotor that rotates around a drive shaft core in a lateral orientation;
A working machine in which the leveling rotor forms a large-diameter portion that performs leveling by driving rotation, and a small-diameter portion that is smaller in diameter than the large-diameter portion at a portion facing the tapered portion of the float.   The working machine according to claim 1, wherein the tapered tip end portion of the float and the large-diameter portion are arranged at a position where they overlap in a side view. The ground leveling rotor forms the large-diameter portion by externally fitting a leveling body on a laterally oriented drive shaft, and the small-diameter portion by externally fitting a protective cover having a smaller diameter than the leveling body on the drive shaft. Forming
The working machine according to claim 1 or 2, wherein a fitting holding portion is formed on an inner periphery so that the protective cover is held in a fixed posture with respect to the driving shaft centered on the driving shaft core. As the parallel quadruple link mechanism that the leveling rotor supports the work device so as to be vertically displaceable, the lower lower link, the upper upper link, and the elevation drive that drives and swings the lower link and the upper link. With a part,
Each base end is supported by a support frame of the working device so that the lower link and the upper link protrude forward, and the positional relationship is such that the upper link is located rearward of the lower link. The work machine according to any one of claims 1 to 3, wherein the working unit is set and the lifting drive unit is disposed above the upper link.   The work machine according to claim 4, further comprising a cover body that covers an upper portion of the lower link and the upper link.

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